Threshold Voltage Shifting Layer Deposition for Work Function Tuning
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Solution Overview
Problem
Conventional device scaling techniques for CMOS devices face challenges in finding suitable conducting materials for gate electrodes, particularly threshold voltage shift materials, which are desired to enhance semiconductor device performance.
Innovation Solution
A method for depositing a threshold voltage shifting layer comprising a metal with the formula M(NxCyOz), where M is a metal, N is nitrogen, C is carbon, and O is oxygen, with x=0 to 5, y=0 to 5, and z=0 to (x+y)≥0.1, using a cyclical deposition process to form a layer with reduced oxygen content or oxygen-free, suitable for future logic structures like gate-all-around transistors and complementary field effect transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional device scaling techniques are used for CMOS devices, then speed and density of integrated circuits are improved, but finding suitable conducting materials for gate electrodes becomes difficult
Solution Approach 1:
The patent changes the compositional parameters of the gate electrode material by forming a threshold voltage shifting layer with specific stoichiometry (M(NxCyOz) where x=0 to 5, y=0 to 5, z=0 to (x+y)≥0.1). This allows tuning of the effective work function and threshold voltage to achieve adaptability in aggressively scaled CMOS devices while maintaining the productivity gains from scaling.
Solution Approach 2:
The patent creates a composite material structure by forming a threshold voltage shifting layer comprising metal nitride, metal carbide, or metal oxynitride/oxycarbide in combination with high-k dielectric materials. This composite approach enables the gate electrode to simultaneously provide the conducting functionality and the threshold voltage shifting capability needed for advanced CMOS scaling.
2Manufacturing precision
If a threshold voltage shifting layer with reduced oxygen content is deposited, then effective oxide thickness penalty is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent employs atomic layer deposition with carefully controlled stoichiometric parameters (x=0 to 5, y=0 to 5, z=0 to (x+y)≥0.1) to deposit the threshold voltage shifting layer. By precisely controlling the nitrogen-to-metal and carbon-to-metal ratios during deposition, the process achieves reduced oxygen content and improved effective oxide thickness control while managing the inherent manufacturing complexity through systematic parameter optimization.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method provides finer tunability and reduces effective oxide thickness penalty, enhancing semiconductor device performance by modulating the effective work function and threshold voltage, while being integration-friendly for advanced transistor designs.
Implementation Method 1
enhancing semiconductor device performance by modulating the effective work function and threshold voltage
Implementation Method 2
A method for depositing a threshold voltage shifting layer comprising a metal with the formula M(NxCyOz)... using a cyclical deposition process
Data Source
AI summary
A method comprising depositing a threshold voltage shifting layer on a substrate, wherein the layer comprises a metal and has the formula M(NxCyOz), wherein M is a metal, N is nitrogen, C is carbon, and O is oxygen, wherein x=0 to 5, y=0 to 5, z=0 to (x+y), wherein (x+y)≥0.1, wherein depositing the threshold voltage shifting layer further comprises one or more of the following operations: providing the substrate having a surface within a reaction chamber; providing a metal-containing precursor comprising the metal to the reaction chamber to contact the surface; providing one or more additional precursors comprising at least one of N or C to the reaction chamber to contact the surface; and/or purging the reaction chamber; and repeating one or more of the disclosed operations or any combination thereof in any order until the threshold voltage shifting layer of a predetermined thickness is deposited on the surface.